/*
 * WPA Supplicant / Crypto wrapper for internal crypto implementation
 * Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "crypto.h"
#include "md5.h"
#include "sha1.h"
#include "rc4.h"
#include "aes.h"
#include "tls/rsa.h"
#include "tls/bignum.h"
#include "tls/asn1.h"


#ifdef CONFIG_CRYPTO_INTERNAL

#ifdef CONFIG_TLS_INTERNAL

/* from des.c */
struct des3_key_s {
        u32 ek[3][32];
        u32 dk[3][32];
};

void des3_key_setup(const u8 *key, struct des3_key_s *dkey);
void des3_encrypt(const u8 *plain, const struct des3_key_s *key, u8 *crypt);
void des3_decrypt(const u8 *crypt, const struct des3_key_s *key, u8 *plain);


struct MD5Context {
        u32 buf[4];
        u32 bits[2];
        u8 in[64];
};

struct SHA1Context {
        u32 state[5];
        u32 count[2];
        unsigned char buffer[64];
};


struct crypto_hash {
        enum crypto_hash_alg alg;
        union {
                struct MD5Context md5;
                struct SHA1Context sha1;
        } u;
        u8 key[64];
        size_t key_len;
};


struct crypto_hash * crypto_hash_init(enum crypto_hash_alg alg, const u8 *key,
                                      size_t key_len)
{
        struct crypto_hash *ctx;
        u8 k_pad[64];
        u8 tk[20];
        size_t i;

        ctx = os_zalloc(sizeof(*ctx));
        if (ctx == NULL)
                return NULL;

        ctx->alg = alg;

        switch (alg) {
        case CRYPTO_HASH_ALG_MD5:
                MD5Init(&ctx->u.md5);
                break;
        case CRYPTO_HASH_ALG_SHA1:
                SHA1Init(&ctx->u.sha1);
                break;
        case CRYPTO_HASH_ALG_HMAC_MD5:
                if (key_len > sizeof(k_pad)) {
                        MD5Init(&ctx->u.md5);
                        MD5Update(&ctx->u.md5, key, key_len);
                        MD5Final(tk, &ctx->u.md5);
                        key = tk;
                        key_len = 16;
                }
                os_memcpy(ctx->key, key, key_len);
                ctx->key_len = key_len;

                os_memcpy(k_pad, key, key_len);
                os_memset(k_pad + key_len, 0, sizeof(k_pad) - key_len);
                for (i = 0; i < sizeof(k_pad); i++)
                        k_pad[i] ^= 0x36;
                MD5Init(&ctx->u.md5);
                MD5Update(&ctx->u.md5, k_pad, sizeof(k_pad));
                break;
        case CRYPTO_HASH_ALG_HMAC_SHA1:
                if (key_len > sizeof(k_pad)) {
                        SHA1Init(&ctx->u.sha1);
                        SHA1Update(&ctx->u.sha1, key, key_len);
                        SHA1Final(tk, &ctx->u.sha1);
                        key = tk;
                        key_len = 20;
                }
                os_memcpy(ctx->key, key, key_len);
                ctx->key_len = key_len;

                os_memcpy(k_pad, key, key_len);
                os_memset(k_pad + key_len, 0, sizeof(k_pad) - key_len);
                for (i = 0; i < sizeof(k_pad); i++)
                        k_pad[i] ^= 0x36;
                SHA1Init(&ctx->u.sha1);
                SHA1Update(&ctx->u.sha1, k_pad, sizeof(k_pad));
                break;
        default:
                os_free(ctx);
                return NULL;
        }

        return ctx;
}


void crypto_hash_update(struct crypto_hash *ctx, const u8 *data, size_t len)
{
        if (ctx == NULL)
                return;

        switch (ctx->alg) {
        case CRYPTO_HASH_ALG_MD5:
        case CRYPTO_HASH_ALG_HMAC_MD5:
                MD5Update(&ctx->u.md5, data, len);
                break;
        case CRYPTO_HASH_ALG_SHA1:
        case CRYPTO_HASH_ALG_HMAC_SHA1:
                SHA1Update(&ctx->u.sha1, data, len);
                break;
        }
}


int crypto_hash_finish(struct crypto_hash *ctx, u8 *mac, size_t *len)
{
        u8 k_pad[64];
        size_t i;

        if (ctx == NULL)
                return -2;

        if (mac == NULL || len == NULL) {
                os_free(ctx);
                return 0;
        }

        switch (ctx->alg) {
        case CRYPTO_HASH_ALG_MD5:
                if (*len < 16) {
                        *len = 16;
                        os_free(ctx);
                        return -1;
                }
                *len = 16;
                MD5Final(mac, &ctx->u.md5);
                break;
        case CRYPTO_HASH_ALG_SHA1:
                if (*len < 20) {
                        *len = 20;
                        os_free(ctx);
                        return -1;
                }
                *len = 20;
                SHA1Final(mac, &ctx->u.sha1);
                break;
        case CRYPTO_HASH_ALG_HMAC_MD5:
                if (*len < 16) {
                        *len = 16;
                        os_free(ctx);
                        return -1;
                }
                *len = 16;

                MD5Final(mac, &ctx->u.md5);

                os_memcpy(k_pad, ctx->key, ctx->key_len);
                os_memset(k_pad + ctx->key_len, 0,
                          sizeof(k_pad) - ctx->key_len);
                for (i = 0; i < sizeof(k_pad); i++)
                        k_pad[i] ^= 0x5c;
                MD5Init(&ctx->u.md5);
                MD5Update(&ctx->u.md5, k_pad, sizeof(k_pad));
                MD5Update(&ctx->u.md5, mac, 16);
                MD5Final(mac, &ctx->u.md5);
                break;
        case CRYPTO_HASH_ALG_HMAC_SHA1:
                if (*len < 20) {
                        *len = 20;
                        os_free(ctx);
                        return -1;
                }
                *len = 20;

                SHA1Final(mac, &ctx->u.sha1);

                os_memcpy(k_pad, ctx->key, ctx->key_len);
                os_memset(k_pad + ctx->key_len, 0,
                          sizeof(k_pad) - ctx->key_len);
                for (i = 0; i < sizeof(k_pad); i++)
                        k_pad[i] ^= 0x5c;
                SHA1Init(&ctx->u.sha1);
                SHA1Update(&ctx->u.sha1, k_pad, sizeof(k_pad));
                SHA1Update(&ctx->u.sha1, mac, 20);
                SHA1Final(mac, &ctx->u.sha1);
                break;
        }

        os_free(ctx);

        return 0;
}


struct crypto_cipher {
        enum crypto_cipher_alg alg;
        union {
                struct {
                        size_t used_bytes;
                        u8 key[16];
                        size_t keylen;
                } rc4;
                struct {
                        u8 cbc[32];
                        size_t block_size;
                        void *ctx_enc;
                        void *ctx_dec;
                } aes;
                struct {
                        struct des3_key_s key;
                        u8 cbc[8];
                } des3;
        } u;
};


struct crypto_cipher * crypto_cipher_init(enum crypto_cipher_alg alg,
                                          const u8 *iv, const u8 *key,
                                          size_t key_len)
{
        struct crypto_cipher *ctx;

        ctx = os_zalloc(sizeof(*ctx));
        if (ctx == NULL)
                return NULL;

        ctx->alg = alg;

        switch (alg) {
        case CRYPTO_CIPHER_ALG_RC4:
                if (key_len > sizeof(ctx->u.rc4.key)) {
                        os_free(ctx);
                        return NULL;
                }
                ctx->u.rc4.keylen = key_len;
                os_memcpy(ctx->u.rc4.key, key, key_len);
                break;
        case CRYPTO_CIPHER_ALG_AES:
                if (key_len > sizeof(ctx->u.aes.cbc)) {
                        os_free(ctx);
                        return NULL;
                }
                ctx->u.aes.ctx_enc = aes_encrypt_init(key, key_len);
                if (ctx->u.aes.ctx_enc == NULL) {
                        os_free(ctx);
                        return NULL;
                }
                ctx->u.aes.ctx_dec = aes_decrypt_init(key, key_len);
                if (ctx->u.aes.ctx_dec == NULL) {
                        aes_encrypt_deinit(ctx->u.aes.ctx_enc);
                        os_free(ctx);
                        return NULL;
                }
                ctx->u.aes.block_size = key_len;
                os_memcpy(ctx->u.aes.cbc, iv, ctx->u.aes.block_size);
                break;
        case CRYPTO_CIPHER_ALG_3DES:
                if (key_len != 24) {
                        os_free(ctx);
                        return NULL;
                }
                des3_key_setup(key, &ctx->u.des3.key);
                os_memcpy(ctx->u.des3.cbc, iv, 8);
                break;
        default:
                os_free(ctx);
                return NULL;
        }

        return ctx;
}


int crypto_cipher_encrypt(struct crypto_cipher *ctx, const u8 *plain,
                          u8 *crypt, size_t len)
{
        size_t i, j, blocks;

        switch (ctx->alg) {
        case CRYPTO_CIPHER_ALG_RC4:
                if (plain != crypt)
                        os_memcpy(crypt, plain, len);
                rc4_skip(ctx->u.rc4.key, ctx->u.rc4.keylen,
                         ctx->u.rc4.used_bytes, crypt, len);
                ctx->u.rc4.used_bytes += len;
                break;
        case CRYPTO_CIPHER_ALG_AES:
                if (len % ctx->u.aes.block_size)
                        return -1;
                blocks = len / ctx->u.aes.block_size;
                for (i = 0; i < blocks; i++) {
                        for (j = 0; j < ctx->u.aes.block_size; j++)
                                ctx->u.aes.cbc[j] ^= plain[j];
                        aes_encrypt(ctx->u.aes.ctx_enc, ctx->u.aes.cbc,
                                    ctx->u.aes.cbc);
                        os_memcpy(crypt, ctx->u.aes.cbc,
                                  ctx->u.aes.block_size);
                        plain += ctx->u.aes.block_size;
                        crypt += ctx->u.aes.block_size;
                }
                break;
        case CRYPTO_CIPHER_ALG_3DES:
                if (len % 8)
                        return -1;
                blocks = len / 8;
                for (i = 0; i < blocks; i++) {
                        for (j = 0; j < 8; j++)
                                ctx->u.des3.cbc[j] ^= plain[j];
                        des3_encrypt(ctx->u.des3.cbc, &ctx->u.des3.key,
                                     ctx->u.des3.cbc);
                        os_memcpy(crypt, ctx->u.des3.cbc, 8);
                        plain += 8;
                        crypt += 8;
                }
                break;
        default:
                return -1;
        }

        return 0;
}


int crypto_cipher_decrypt(struct crypto_cipher *ctx, const u8 *crypt,
                          u8 *plain, size_t len)
{
        size_t i, j, blocks;
        u8 tmp[32];

        switch (ctx->alg) {
        case CRYPTO_CIPHER_ALG_RC4:
                if (plain != crypt)
                        os_memcpy(plain, crypt, len);
                rc4_skip(ctx->u.rc4.key, ctx->u.rc4.keylen,
                         ctx->u.rc4.used_bytes, plain, len);
                ctx->u.rc4.used_bytes += len;
                break;
        case CRYPTO_CIPHER_ALG_AES:
                if (len % ctx->u.aes.block_size)
                        return -1;
                blocks = len / ctx->u.aes.block_size;
                for (i = 0; i < blocks; i++) {
                        os_memcpy(tmp, crypt, ctx->u.aes.block_size);
                        aes_decrypt(ctx->u.aes.ctx_dec, crypt, plain);
                        for (j = 0; j < ctx->u.aes.block_size; j++)
                                plain[j] ^= ctx->u.aes.cbc[j];
                        os_memcpy(ctx->u.aes.cbc, tmp, ctx->u.aes.block_size);
                        plain += ctx->u.aes.block_size;
                        crypt += ctx->u.aes.block_size;
                }
                break;
        case CRYPTO_CIPHER_ALG_3DES:
                if (len % 8)
                        return -1;
                blocks = len / 8;
                for (i = 0; i < blocks; i++) {
                        os_memcpy(tmp, crypt, 8);
                        des3_decrypt(crypt, &ctx->u.des3.key, plain);
                        for (j = 0; j < 8; j++)
                                plain[j] ^= ctx->u.des3.cbc[j];
                        os_memcpy(ctx->u.des3.cbc, tmp, 8);
                        plain += 8;
                        crypt += 8;
                }
                break;
        default:
                return -1;
        }

        return 0;
}


void crypto_cipher_deinit(struct crypto_cipher *ctx)
{
        switch (ctx->alg) {
        case CRYPTO_CIPHER_ALG_AES:
                aes_encrypt_deinit(ctx->u.aes.ctx_enc);
                aes_decrypt_deinit(ctx->u.aes.ctx_dec);
                break;
        case CRYPTO_CIPHER_ALG_3DES:
                break;
        default:
                break;
        }
        os_free(ctx);
}


/* Dummy structures; these are just typecast to struct crypto_rsa_key */
struct crypto_public_key;
struct crypto_private_key;


struct crypto_public_key * crypto_public_key_import(const u8 *key, size_t len)
{
        return (struct crypto_public_key *)
                crypto_rsa_import_public_key(key, len);
}


#ifdef EAP_TLS_FUNCS
static struct crypto_private_key *
crypto_pkcs8_key_import(const u8 *buf, size_t len)
{
        struct asn1_hdr hdr;
        const u8 *pos, *end;
        struct bignum *zero;
        struct asn1_oid oid;
        char obuf[80];

        /* PKCS #8, Chapter 6 */

        /* PrivateKeyInfo ::= SEQUENCE */
        if (asn1_get_next(buf, len, &hdr) < 0 ||
            hdr.class != ASN1_CLASS_UNIVERSAL ||
            hdr.tag != ASN1_TAG_SEQUENCE) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Does not start with PKCS #8 "
                           "header (SEQUENCE); assume PKCS #8 not used");
                return NULL;
        }
        pos = hdr.payload;
        end = pos + hdr.length;

        /* version Version (Version ::= INTEGER) */
        if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
            hdr.class != ASN1_CLASS_UNIVERSAL || hdr.tag != ASN1_TAG_INTEGER) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Expected INTEGER - found "
                           "class %d tag 0x%x; assume PKCS #8 not used",
                           hdr.class, hdr.tag);
                return NULL;
        }

        zero = bignum_init();
        if (zero == NULL)
                return NULL;

        if (bignum_set_unsigned_bin(zero, hdr.payload, hdr.length) < 0) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Failed to parse INTEGER");
                bignum_deinit(zero);
                return NULL;
        }
        pos = hdr.payload + hdr.length;

        if (bignum_cmp_d(zero, 0) != 0) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Expected zero INTEGER in the "
                           "beginning of private key; not found; assume "
                           "PKCS #8 not used");
                bignum_deinit(zero);
                return NULL;
        }
        bignum_deinit(zero);

        /* privateKeyAlgorithm PrivateKeyAlgorithmIdentifier
         * (PrivateKeyAlgorithmIdentifier ::= AlgorithmIdentifier) */
        if (asn1_get_next(pos, len, &hdr) < 0 ||
            hdr.class != ASN1_CLASS_UNIVERSAL ||
            hdr.tag != ASN1_TAG_SEQUENCE) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Expected SEQUENCE "
                           "(AlgorithmIdentifier) - found class %d tag 0x%x; "
                           "assume PKCS #8 not used",
                           hdr.class, hdr.tag);
                return NULL;
        }

        if (asn1_get_oid(hdr.payload, hdr.length, &oid, &pos)) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Failed to parse OID "
                           "(algorithm); assume PKCS #8 not used");
                return NULL;
        }

        asn1_oid_to_str(&oid, obuf, sizeof(obuf));
        wpa_printf(MSG_DEBUG, "PKCS #8: algorithm=%s", obuf);

        if (oid.len != 7 ||
            oid.oid[0] != 1 /* iso */ ||
            oid.oid[1] != 2 /* member-body */ ||
            oid.oid[2] != 840 /* us */ ||
            oid.oid[3] != 113549 /* rsadsi */ ||
            oid.oid[4] != 1 /* pkcs */ ||
            oid.oid[5] != 1 /* pkcs-1 */ ||
            oid.oid[6] != 1 /* rsaEncryption */) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Unsupported private key "
                           "algorithm %s", obuf);
                return NULL;
        }

        pos = hdr.payload + hdr.length;

        /* privateKey PrivateKey (PrivateKey ::= OCTET STRING) */
        if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
            hdr.class != ASN1_CLASS_UNIVERSAL ||
            hdr.tag != ASN1_TAG_OCTETSTRING) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Expected OCTETSTRING "
                           "(privateKey) - found class %d tag 0x%x",
                           hdr.class, hdr.tag);
                return NULL;
        }
        wpa_printf(MSG_DEBUG, "PKCS #8: Try to parse RSAPrivateKey");

        return (struct crypto_private_key *)
                crypto_rsa_import_private_key(hdr.payload, hdr.length);
}
#endif /* EAP_TLS_FUNCS */


struct crypto_private_key * crypto_private_key_import(const u8 *key,
                                                      size_t len)
{
        struct crypto_private_key *res;

        /* First, check for possible PKCS #8 encoding */
        res = crypto_pkcs8_key_import(key, len);
        if (res)
                return res;

        /* Not PKCS#8, so try to import PKCS #1 encoded RSA private key */
        wpa_printf(MSG_DEBUG, "Trying to parse PKCS #1 encoded RSA private "
                   "key");
        return (struct crypto_private_key *)
                crypto_rsa_import_private_key(key, len);
}


struct crypto_public_key * crypto_public_key_from_cert(const u8 *buf,
                                                       size_t len)
{
        /* No X.509 support in crypto_internal.c */
        return NULL;
}


static int pkcs1_generate_encryption_block(u8 block_type, size_t modlen,
                                           const u8 *in, size_t inlen,
                                           u8 *out, size_t *outlen)
{
        size_t ps_len;
        u8 *pos;

        /*
         * PKCS #1 v1.5, 8.1:
         *
         * EB = 00 || BT || PS || 00 || D
         * BT = 00 or 01 for private-key operation; 02 for public-key operation
         * PS = k-3-||D||; at least eight octets
         * (BT=0: PS=0x00, BT=1: PS=0xff, BT=2: PS=pseudorandom non-zero)
         * k = length of modulus in octets (modlen)
         */

        if (modlen < 12 || modlen > *outlen || inlen > modlen - 11) {
                wpa_printf(MSG_DEBUG, "PKCS #1: %s - Invalid buffer "
                           "lengths (modlen=%lu outlen=%lu inlen=%lu)",
                           __func__, (unsigned long) modlen,
                           (unsigned long) *outlen,
                           (unsigned long) inlen);
                return -1;
        }

        pos = out;
        *pos++ = 0x00;
        *pos++ = block_type; /* BT */
        ps_len = modlen - inlen - 3;
        switch (block_type) {
        case 0:
                os_memset(pos, 0x00, ps_len);
                pos += ps_len;
                break;
        case 1:
                os_memset(pos, 0xff, ps_len);
                pos += ps_len;
                break;
        case 2:
                if (os_get_random(pos, ps_len) < 0) {
                        wpa_printf(MSG_DEBUG, "PKCS #1: %s - Failed to get "
                                   "random data for PS", __func__);
                        return -1;
                }
                while (ps_len--) {
                        if (*pos == 0x00)
                                *pos = 0x01;
                        pos++;
                }
                break;
        default:
                wpa_printf(MSG_DEBUG, "PKCS #1: %s - Unsupported block type "
                           "%d", __func__, block_type);
                return -1;
        }
        *pos++ = 0x00;
        os_memcpy(pos, in, inlen); /* D */

        return 0;
}


static int crypto_rsa_encrypt_pkcs1(int block_type, struct crypto_rsa_key *key,
                                    int use_private,
                                    const u8 *in, size_t inlen,
                                    u8 *out, size_t *outlen)
{
        size_t modlen;

        modlen = crypto_rsa_get_modulus_len(key);

        if (pkcs1_generate_encryption_block(block_type, modlen, in, inlen,
                                            out, outlen) < 0)
                return -1;

        return crypto_rsa_exptmod(out, modlen, out, outlen, key, use_private);
}


int crypto_public_key_encrypt_pkcs1_v15(struct crypto_public_key *key,
                                        const u8 *in, size_t inlen,
                                        u8 *out, size_t *outlen)
{
        return crypto_rsa_encrypt_pkcs1(2, (struct crypto_rsa_key *) key,
                                        0, in, inlen, out, outlen);
}


int crypto_private_key_decrypt_pkcs1_v15(struct crypto_private_key *key,
                                         const u8 *in, size_t inlen,
                                         u8 *out, size_t *outlen)
{
        struct crypto_rsa_key *rkey = (struct crypto_rsa_key *) key;
        int res;
        u8 *pos, *end;

        res = crypto_rsa_exptmod(in, inlen, out, outlen, rkey, 1);
        if (res)
                return res;

        if (*outlen < 2 || out[0] != 0 || out[1] != 2)
                return -1;

        /* Skip PS (pseudorandom non-zero octets) */
        pos = out + 2;
        end = out + *outlen;
        while (*pos && pos < end)
                pos++;
        if (pos == end)
                return -1;
        pos++;

        *outlen -= pos - out;

        /* Strip PKCS #1 header */
        os_memmove(out, pos, *outlen);

        return 0;
}


int crypto_private_key_sign_pkcs1(struct crypto_private_key *key,
                                  const u8 *in, size_t inlen,
                                  u8 *out, size_t *outlen)
{
        return crypto_rsa_encrypt_pkcs1(1, (struct crypto_rsa_key *) key,
                                        1, in, inlen, out, outlen);
}


void crypto_public_key_free(struct crypto_public_key *key)
{
        crypto_rsa_free((struct crypto_rsa_key *) key);
}


void crypto_private_key_free(struct crypto_private_key *key)
{
        crypto_rsa_free((struct crypto_rsa_key *) key);
}


int crypto_public_key_decrypt_pkcs1(struct crypto_public_key *key,
                                    const u8 *crypt, size_t crypt_len,
                                    u8 *plain, size_t *plain_len)
{
        size_t len;
        u8 *pos;

        len = *plain_len;
        if (crypto_rsa_exptmod(crypt, crypt_len, plain, &len,
                               (struct crypto_rsa_key *) key, 0) < 0)
                return -1;

        /*
         * PKCS #1 v1.5, 8.1:
         *
         * EB = 00 || BT || PS || 00 || D
         * BT = 00 or 01
         * PS = k-3-||D|| times (00 if BT=00) or (FF if BT=01)
         * k = length of modulus in octets
         */

        if (len < 3 + 8 + 16 /* min hash len */ ||
            plain[0] != 0x00 || (plain[1] != 0x00 && plain[1] != 0x01)) {
                wpa_printf(MSG_INFO, "LibTomCrypt: Invalid signature EB "
                           "structure");
                return -1;
        }

        pos = plain + 3;
        if (plain[1] == 0x00) {
                /* BT = 00 */
                if (plain[2] != 0x00) {
                        wpa_printf(MSG_INFO, "LibTomCrypt: Invalid signature "
                                   "PS (BT=00)");
                        return -1;
                }
                while (pos + 1 < plain + len && *pos == 0x00 && pos[1] == 0x00)
                        pos++;
        } else {
                /* BT = 01 */
                if (plain[2] != 0xff) {
                        wpa_printf(MSG_INFO, "LibTomCrypt: Invalid signature "
                                   "PS (BT=01)");
                        return -1;
                }
                while (pos < plain + len && *pos == 0xff)
                        pos++;
        }

        if (pos - plain - 2 < 8) {
                /* PKCS #1 v1.5, 8.1: At least eight octets long PS */
                wpa_printf(MSG_INFO, "LibTomCrypt: Too short signature "
                           "padding");
                return -1;
        }

        if (pos + 16 /* min hash len */ >= plain + len || *pos != 0x00) {
                wpa_printf(MSG_INFO, "LibTomCrypt: Invalid signature EB "
                           "structure (2)");
                return -1;
        }
        pos++;
        len -= pos - plain;

        /* Strip PKCS #1 header */
        os_memmove(plain, pos, len);
        *plain_len = len;

        return 0;
}


int crypto_global_init(void)
{
        return 0;
}


void crypto_global_deinit(void)
{
}
#endif /* CONFIG_TLS_INTERNAL */


#if defined(EAP_FAST) || defined(CONFIG_WPS)

int crypto_mod_exp(const u8 *base, size_t base_len,
                   const u8 *power, size_t power_len,
                   const u8 *modulus, size_t modulus_len,
                   u8 *result, size_t *result_len)
{
        struct bignum *bn_base, *bn_exp, *bn_modulus, *bn_result;
        int ret = -1;

        bn_base = bignum_init();
        bn_exp = bignum_init();
        bn_modulus = bignum_init();
        bn_result = bignum_init();

        if (bn_base == NULL || bn_exp == NULL || bn_modulus == NULL ||
            bn_result == NULL)
                goto error;

        if (bignum_set_unsigned_bin(bn_base, base, base_len) < 0 ||
            bignum_set_unsigned_bin(bn_exp, power, power_len) < 0 ||
            bignum_set_unsigned_bin(bn_modulus, modulus, modulus_len) < 0)
                goto error;

        if (bignum_exptmod(bn_base, bn_exp, bn_modulus, bn_result) < 0)
                goto error;

        ret = bignum_get_unsigned_bin(bn_result, result, result_len);

error:
        bignum_deinit(bn_base);
        bignum_deinit(bn_exp);
        bignum_deinit(bn_modulus);
        bignum_deinit(bn_result);
        return ret;
}

#endif /* EAP_FAST || CONFIG_WPS */


#endif /* CONFIG_CRYPTO_INTERNAL */
